"The audio tools, EQ, dynamics etc are overall very smooth sounding in PT. In many cases there is no counterpart in Sonar and similar VSTs are coarse sounding by comparison."
This is really surprising to hear!! Most other rooms we work with that have both Sonar and PT say just the opposite. Of the stock plugin set that comes with PT, only the new Channel Strip can compete with most modern day emulations for quality sound and the Bomb factory 1176 emulation is really dated now. The air stuff is decent and serviceable. The bizarro backwards behavior of the Channel Strip's gate and Comp section are truly baffling however.
Sonar's plug set is heads and shoulders above by comparison and the Pro Channel FX are outstanding, especially the Soft Tube, Vocal Strip, and Mix Bus comps. Even if you just spring for the CA-2A and the Concrete Limiter, you basicly have the bulk of our UAD-1 library at 'HALF' the CPU hit and latency.
I love PT for tracking but for mixing and especially bussing, sonar kills it for workflow and sound quality. YMMV